One mode of insulin therapy for diabetes is injection of insulin via disposable syringes. Generally, a user removes a safety cap disposed over the needle on the syringe, pierces a cover of an insulin container with the needle, and withdraws a predetermined amount of insulin to prepare the insulin for injection. The user then pierces his or her skin with the needle and injects the insulin. After injecting the insulin, the syringe is discarded.
Conventional disposable syringes generally include a molded cylindrical barrel, a needle hub fastened to the barrel, and a needle disposed in the needle hub to communicate liquids disposed in the barrel by operation of a plunger. Syringes are marked along the barrel with visual indicators of the volume of liquid disposed within the barrel to allow a user to withdraw and inject the correct volume of medication. Conventional molded needle hubs are not separately marked after assembly, making it difficult to ascertain the properties of the needle.
In insulin treatment, there are different insulin concentrations available to users. To accommodate the different concentrations of insulin, the markings on the syringe barrel may correspond to units of insulin of a particular insulin concentration. Therefore, if two co-habitating insulin users have different insulin requirements, it may be possible for one of the users to inadvertently use an incorrect syringe and inject an incorrect insulin dosage.